Vertically hanging plastic strips arranged side-by-side, or in an overlapping arrangement, are used in many industrial and commercial applications to provide a flexible barrier to air, insects, noise, vapors, moisture, etc. A strip door system, which provides such barrier, only minimally disrupts the passage of product, personnel or vehicles through a doorway, or the like, as the vertically hanging plastic strips are easily bent to provide an opening for entry or exit. An important application for strip door systems, which provide a significant savings in energy consumption, is on openings into freezers and coolers in warehouse facilities, food processing areas, restaurants, etc.
Strip door systems are typically assembled by hanging a plurality of flexible plastic strips, having a width of 8-16 inches and a thickness of 0.060 to 0.160 inches, which are produced from PVC material. The strips typically are hung to span a vertically oriented plane, such as between side jams of a doorway. The strips typically have an overlap of 25-100%, for example, for a 50% overlap, on a given strip, 25% of its width, at each edge, would be overlapped with an adjacent strip.
The vertically hanging strips are usually hung from a uniformity spaced series of studs disposed at or near a header of a doorway. The studs are most often fixed to a plate, or the like, to form a hanger, and the hanger is attached to the header or a wall above the doorway. Many different hangers are known for hanging the plastic strips.
FIG. 1 shows a known flexible strip door system for describing a general configuration of a strip door system in which a hanger of the present invention would be used. In FIG. 1, an opening 1 in wall 2 is provided with a flexible plastic strip door 3 having elongated flexible plastic strips 4 arranged in an overlapping pattern with areas of overlapping indicated at 5. The strips 4 are hung from a hanger 6 having protruding studs 7 arranged in a uniform spacing along the length of the hanger. The plastic strips 4 have uniformily spaced apertures 8, along an upper portion, which correspond in spacing with the studs 7 of the hanger. The spacing arrangement of the studs and the apertures allow for overlap of 25 to 100%, or no overlap, wherein edges of the strips are placed abutting edges of adjacent strips.
The system depicted in FIG. 1 has an overlap of about 50%, that is 50% of each strip is overlapped by other strips. Although not shown, some type of retaining device is necessary to prevent the strips from sliding off the studs when the strips are encountered by personnel or equipment passing through the opening. In U.S. patent application Ser. No. 10/406,527 entitled “Flexible-Strip Hanger for a Strip Door System and Method of Making Same”, filed Apr. 3, 2003, a hinged cover prevents the plastic strips from sliding off the studs.
Plastic strip door systems, as described above are very durable as they can be subjected to heavy usage by personnel or equipment passing through them. In particular, fork lifts or other commercial and industrial type equipment often subject the plastic strips to harsh usage, including tearing away of the strips, if caught on such equipment or caught on the product being moved. Such harsh usage, as well as normal everyday usage, necessitates the plastic strips being replaced from time to time. Because of the typical locations of the hangers, that is at a location requiring the use of a ladder, and/or at cold or below freezing environments, replacement is often difficult and dangerous, and can require the use of more than one person to carry out the replacement.
One known hanger has spaced studs on a backing plate along with a strip retaining bar, which requires the use of tools to secure the bar in place. Another known hanger, although it requires no tools for installing the strips, relies solely on studs having an enlarged end to prevent the strips from sliding off. In such a system an aperture in the plastic strip, which slides over the stud, must be very accurately formed so as to fit over the stud, yet be retained by the enlarged end. In the same system, a strip having the properly sized aperture can be difficult to slide over the enlarged end, if the material of the strip is at a low temperature in a cooler or freezer application. Many retaining systems are known, however they all have undesirable features.